1. Technical Field
The present disclosure relates to cathode material of lithium batteries and methods for fabricating the same.
2. Description of Related Art
Lithium batteries are used in various portable devices, such as notebook PCs, mobile phones, and digital cameras because of their small weight, high discharge voltage, long cyclic life, and high energy density compared with conventional lead storage batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries.
Among various cathode materials, transition metal oxides and mixed transition metal oxides have received much attention because of their relatively high charge/discharge capacities in the lithium batteries. Lithium iron phosphate (e.g. LiFePO4), and lithium vanadium phosphate (e.g. Li3V2(PO4)3) are two widely used cathode active materials. Lithium iron phosphate has the advantage of high specific capacity, but has the disadvantage of bad performance at low temperatures. Lithium vanadium phosphate has good performance at low temperatures, but low specific capacity. As such, there is a composite cathode material including both lithium iron phosphate and lithium vanadium phosphate provided in, “Improving electrochemical properties of lithium iron phosphate by addition of vanadium,” Yang M R, Ke W, Wu S H. J Power Sources, 2007, 165: 646-650. However, in the composite cathode material, lithium iron phosphate and lithium vanadium phosphate are disorderly disposed, which means that some of the lithium iron phosphate cannot contact with the electrolyte when used in a lithium battery. As such, lithium iron phosphate cannot be dispersed in the electrolyte easily and quickly, thereby negatively impacting electrochemical properties of the electrode material of the lithium battery.
What is needed, therefore, is a lithium battery cathode composite material and method for making the same that can overcome the above-described shortcomings.